Abstract: This case report is about one genetically specified diagnosed infant case of Caroli syndrome with autosomal recessive polycystic kidney disease (ARPKD) in China. The patient in this case report was an eightmonth infant boy with an atypical onset and the main clinical manifestation was non-symptomatic enlargement of the liver and kidneys. The imaging study demonstrated a diffused cystic dilatation of intrahepatic bile ducts as well as polycystic changes in bilateral kidneys. The basic blood biochemical tests indicated a normal hepatorenal function. Four serum biomarkers of hepatic fibrosis were all elevated and the urine test for an early detection of the renal injury was positive. The genetic sequencing proved two heterozygous missense mutations of polycystic kidney and hepatic disease 1 （PKHD1） gene, c.9292G>A and c.2507T>C, inherited from each of his parents respectively. The former was a novel mutation that had been verified as disease causing through the predicting software while the latter had been reported from one recent case study on Chinese twins, which was possibly unique among Chinese population. The relations between the gene type and the clinical phenotype were not clarified yet. Up till a follow-up eleven months later after the discharge, the patient had a normal hepatorenal function without occurrence of any severe complication yet. The clinical symptoms of Caroli syndrome with ARPKD at infant stage were atypical and the enlargement of liver and kidney was usually the sole symptom. From the above systematic retrospective clinical analysis, as well as the relevant literature review, it’s been concluded that the features of the hepatorenal images in patients with Caroli syndrome and ARPKD were distinctive. Genetic testing combined with the imaging study benefits a definite diagnosis as well as a diffe-rentiation from other hepatorenal fibrocystic diseases. Specific to the long-term management of this kind of patients, it’s necessary to schedule a regular follow-up to monitor the hepatorenal function and the occurrence of various complications for an appropriate intervention, meantime to devote efforts to the genetic counseling work for the patients’ family.

Key words: Infant, Caroli syndrome, Polycystic kidney, autosomal recessive, Gene, Mutation